...Or lack of
Since everyone is interested about commercialisation, I thought I should say something.
My current plans are to keep Indigo free, for personal and limited commercial use. The limits on commercial use are described in the license.txt in the latest distributions: basically it's a restriction that you can't charge directly for rendering with Indigo off a renderfarm.
There's also the redistribution restriction - no redistribution please.

I don't want to sell Indigo in single copies like Vray or Maxwell or whatever, for a few reasons:
* support - not my idea of a good time
* bugfixing for x thousand people - also not my idea of a good time
* Indigo is not really user-friendly enough to charge for.
* It's nice to be free. I like that people use my software
etc.. etc..

What I am interested in doing is licensing Indigo to other companies, so that they can use it as, for example, a rendering backend for modelling software, or to run as a backend renderer on a remote renderfarm.

The advantage of this approach is that I get to keep Indigo free for you guys (and gals?), so we can keep our nice community of poor students etc... , while still hopefully making some money for me at some point.

That said, if things don't work out as planned (your life changes in some way, you get busy with something else etc) I hope you would consider releasing the source as a gift to the community. It would be such a shame if indigo stopped developing and stayed closed source only to decay on hard drives the world over.

That is a big if and I want to make it clear that I wish you all the best with this venture!